obj2fs-hooks v1.0.0

obj2fs-hooks

A set of hooks that can be injected into your functional components to enhance their behavior. Specifically, to make these components persistable to file system as JSON strings.

Usage

In the class that you want to enhance with this HOC

import Obj2fsHooks from 'obj2fs-hooks'

Then declare your like this:

function Account({ publicKey } = { publicKey: '' }) {// have to make publicKey optional
    this.publicKey = publicKey
    this.balance = 0
    this.stake = 0

  // this method defines behavior of Account data type,
  // which will be preserved after you deserialize the object from JSON
  this.addBalance({ amount }) {
    this.balance += amount
  }

  return Object.assign(
    this,
    Obj2fsHooks(this),
  )
}

export default Account // exporting enhanced Account

Enhancing Account with Obj2fsHooks adds 6 methods to Account type.

setKey(KEY) which associates an Object with a KEY (path on disk), returns this so can be chained

stringify() which is self explanatory -- returns JSON string representation of the object.

parse(json) which returns object instance of correct type.

store() which saves this object as JSON string to disk with name KEY. It will create the file if it does not exist.

retrieve() which loads object instance of correct type from disk. If the file is not found it will throw exception. throw new Error('No such key or file name found on disk')

retrieveOrNew() which loads object instance of correct type from disk. If the file is not found it will create a new file contents of an object initialized with default constructor and then return it. This method should never fail.

Here are examples how to use the Account object:

import Account from './account'

let account = new Account({ publicKey: 'some public key' }) // constructor with required parameter
const amount = 100
account.addBalance({ amount })

let jsonAccount = account.stringify()
// jsonAccount will have the right amount

// now let's re-created another instance of the Account object from JSON string
let generatedAccount = new Account().parse(jsonAccount)
// can still call the addBalance method, because the object is of the right type
generatedAccount.addBalance({ amount })

console.log(generatedAccount.balance) // ----> 200

// here is how to store/retrieve account by key
jsonAccount = account.setKey(key).store()
// jsonAccount will be saved to disk as JSON string

// now let's re-created another instance of the Account object from file on disk
generatedAccount = new Account().setKey(key).retrieve()
// can still call the addBalance method, because the object is of the right type
generatedAccount.addBalance({ amount })

console.log(generatedAccount.balance) // ----> 300

Future

Currently only synch version is supported. There are plans to include asynch methods at some point.